1. Field of the Invention
The present invention relates to apparatus and methods for upconverting content data including plural components.
2. Description of the Related Art
Hitherto, various techniques have been researched regarding upconversion processing for realizing more realistic and powerful images and sounds, such as a technique for enhancing video image quality and sound quality.
Along with an increase in display screen size and resolution, a demand for products equipped with the image quality enhancing technique would grow in the future. For example, a technique for converting a standard-definition (SD) video image to a high-definition (HD) video image (resolution conversion) through classification/adaptive processing has been under study. Further, various techniques have been proposed for enhancing the image quality, such as a technique for generating a high-quality video image through γ correction (gamma correction) or contour correction.
Japanese Patent Application Laid-Open No. 07-321662 discusses a technique that combines time-part processing and frequency-part processing to increase processing accuracy. Japanese Patent Application Laid-Open No. 2004-246526 discusses a technique for achieving a high-accuracy processing result which more precisely corresponds to real events, in consideration of the real events where data is obtained.
Further, a demand for products equipped with the sound quality enhancing technique has been increased. Japanese Patent Application Laid-Open No. 09-261071 discusses a technique for converting a format of multi-bit audio data having a sampling frequency fS and extracted from a compact disc (CD) into 1-bit audio data having a sampling frequency m*fS (m is an integer). This technique enables reproduction of even a subtle sound or nuance that could not be realized by the CD.
There are two methods for upconversion processing, that is, a method for processing content data concurrently with reproduction of the data and a method of processing content data over time, not concurrently with the reproduction.
For example, in the case of raising video image quality through dynamic gamma correction, content data can be processed almost concurrently with reproduction. On the other hand, in the case of raising video image quality through resolution conversion or raising sound quality through format conversion, in some cases, content data could not be processed concurrently with reproduction because of its high processing load.
For example, in the case of converting a format of multi-bit audio data extracted from a CD into 1-bit audio data as described above, if a system throughput is not so high, processing takes several times as long as the reproduction time of music. In this case, content data may be temporarily stored in a recording medium and then gradually upconverted. In the case of gradually upconverting data in this way, if a processing time is long, the following problem occurs. That is, when a user desires to reproduce content data being processed, the content data cannot be reproduced.
According to the moving pictures experts group 2 (MPEG-2) standard, a standard adopted for digital broadcasting standards and a package media such as digital versatile disc (DVD), plural elementary streams (ESs) are multiplexed. To be specific, plural components, for example, video images, sounds, and additional information are multiplexed.
According to this standard, plural video components are multiplexed to enable a user to view multi-angle video images (video images taken with plural cameras at different angles) at the same time or by freely switching the angles. Further, it is possible to support various languages by multiplexing plural audio components.
At the time of upconverting content data obtained by multiplexing plural components (elementary streams), if all components are upconverted in parallel, a high processing load is imposed on the system. However, it is supposedly unnecessary to upconvert all components at the same time in many cases.
For example, if a user wants to view only a main video image of multi-angle video images, it is preferred to enhance a quality of the main video image ahead of (prior to) sub video images. If a user wants to view a music program with a high sound quality, it is preferred to enhance a sound quality ahead of (prior to) an image quality.